Answer: The heat index is an index that combines air temperature and relative humidity, in shaded areas, to posit a human-perceived equivalent temperature, as how hot it would feel if the humidity were some other value in the shade.
Explanation: did the test
Carbon atoms have 4 valence electrons. That allows them to make 4 covalent bonds. That means they can make really big molecules. All the organic molecules have Carbon in them.
Tundra and deserts are two biomes of the world which represent the extreme form of climates. Tudra is the coldest region of the earth while desert represent the hottest zones of the earth. But whats the most common thing in these extreme zones is that they receive very less precipitation throughout the year (less than 25 cm).
Therefore, flora of the desert and Tundra have some special adaptations to survive without sufficient amount of water.
Let's see what are those:
- The height of plants growing in Tundra is very less like lesser than 1 foot. The short structure of the plants helps them to get more heat from the dark soil and helps to survive freezing. The short height lets them stay protected from harsh effects of cold or snow.
- The plants in tundra grow in groups or clumps that helps them in surviving the attacks of ice particles or snow balls. For example: lousewort and Arctic crocus.
- Some flora of tundra has ability to grow even in the complete lack of water for several years.This is because they have waxy layers that cover the leaves and store maximum water for the periods of no availability.
- Some plants have hair on the surface of stems that trap maximum heat and protect the plant from heat and extreme forms of wind. For example: Arctic crocus.
- Desert plants not only have physiological but also morphological adaptations to survive heat stress and shortage of water. Their stems, roots and leaves are fleshy and help them to store water for a large period of time. For example: Cactus
- Many desert plants like <em>xerophytic bromeliads</em> and <em>epiphytic orchids </em>contain a system alternate of photosynthesis called CAM (Crassulacean Acid Metabolism). This process helps the plant to open the stomata at night for exchange of gases and accumulate CO2. In day, stomata are closed and the CO2 is used for photosynthesis. This is an adaptation, because during night when temperature is low, CAM plants lose less water as compared to what normal plants lose during day.
- Some plants have extremely large roots that absorb maximum water from soil and compensate the plant's loss of water due to heat. For example: Phreatophytes.
- Some Perennial plants have adapted the mechanism to stay in condition of rest or dormant during extreme heat. They get back to normal life when weather become a bit better.
Hope it helps! :)
It is D. Sponges can move but not all, they are soft not hard so not B. They do not make food they absorb it so it D
The correct option is B.
Idea models refers to those models that are used to show the relationships that exist between abstract concepts. The model is used basically to bring about desired changes and it normally used in business and other sectors to visualize how an idea might work out. Idea models are usually presented in form of graphs and equations, the variables in these graphs and equations show the relationships between the variables that are been considered.